Welcome to space travel - suite 2
The U.S. Declaration of Independence contains the inalienable rights of man, namely life, liberty and the pursuit of happiness. There are many people not just in the United States but also throughout the world who desire space travel but are prevented from doing so, largely due to cost. This is a constraint on their individual freedom, their liberty and their right to pursue self-happiness for the benefit of all humankind. Space travel must be opened up to the world at large and humanity allowed to continue to explore the cosmos.
. Travel to Suborbital level is when a Spacecraft reaches space at 100 km (62 miles) or higher but does not have the forward velocity to go into orbit (e.g. 7.7km/s at 300 km)
. Travel to Orbital level is when a spacecraft go to Low Earth Orbit (LEO), between 180-3000 km, at Higher Earth Orbit (HEO) –Geocentric, at 35,786 km
.Deep Space Travel is when a spacecraft go at Lagrange points, Moon, Asteroids, Mars and beyond
HSF Timeline & Mission Drivers
Inner Solar System (through 2050) – Near-Earth, Cis-Lunar & Mars
. Achievable via Chemical Propulsion, Split–Chemical/SEP, Hybrid-Chemical/SEP or NTP/NEP Ø Facilitate Econo-Space Development & Commercial Opportunities
. Establish Outposts, Permanent Bases & Colonies
Outer Solar System (2050 to 2100) – Beyond Mars
. Requires Highly Energetic Processes/Concepts beyond NTP
. Harsh Space Radiation Environment & Sustained Zero Gravity Impose Strict Biological Constraints
. Enable In situ Human Exploration
Source: Space Technology Mission Directorate, NASA, Planned & Future Missions Human Exploration of the Solar System by 2100, April, 4-6, 2017.
Propulsion without fuel!
We can do it in using techniques of Aeroassit, which includes Aerocapture, Aerobraking, entry and Aerogravity Assist maneuvers.
So, when a spacecraft do many passes through the atmosphere of a planet with only small changes during each pass, that means passing from a larger eccentricity to a smaller, it makes Aerobraking maneuver. During a single pass, the initial and the final states of the spacecraft are bound orbits at the primary. Today example of that it’s the Grand Finale of Cassini on Saturn planet in September 2017. Learn more about that. See below.
Unless many variants exist of this maneuver, if a spacecraft enter into a planet’s atmosphere from a bound or unbound orbit and makes a fully decelerated state, it makes an atmospheric entry.
The spacecraft can entry directly in decreasing monotonically its altitude throughout the entry maneuver. Because it is direct, it can be landing on a solid or liquid surface (like Titan’s lakes), or complete a mission while still in the atmosphere, as giant planet entry probes as well as a Venus balloon.
A second variant used is the “skip entry”, where the spacecraft enters the atmosphere and decelerates partially, exit and then re-enter for a final deceleration. This latter method is often applied to very high-energy entries, allowing more gradual deceleration and increased landing location accuracy.
So, if the location is not important, the direct entry maneuver can be applicate without flight path control. But, if it is important and has relatively small tolerances, a guided entry might be more appropriate. That is why, Aerobraking is more challenging than Aerocapture, but necessary, for critical payload like the Mars Science Lander or “Curiosity.” In that latter case, operational team use a flight path control during the hypersonic phase of the entry.
When a spacecraft, in addition to the gravitational forces, uses the aerodynamic forces generated during a flight through a body’s atmosphere, it maneuvers in Aerogravity assist. That method is useful for a body with a weak gravitational field that cannot provide the hyperbolic bending angle needed for a near-optimal gravity assist maneuver, but with a relative atmosphere, it can generate aerodynamic forces sufficient to achieve it.
Unlike Aerocapture, the approach and departure orbits of an Aerogravity assist maneuver are unbound with respect to the body whose atmosphere is used, so the vehicle’s ultimate destination is usually elsewhere.
Most examples in the literature describe Aerogravity assist as a means to achieve extremely high heliocentric velocities (on the order of 50–100 km/s) or high-energy trajectories to the outer solar system, applications that would require significant advances in thermal protection system technology.
But an Aerogravity assist maneuver can also decrease a vehicle’s orbital energy relative to a third body. For example, a spacecraft could use a relatively gentle Aerogravity assist in Titan’s atmosphere to capture into Saturn orbit.
Potential Benefits of Aerocapture
For a particular launch vehicle, there are three categories of potential benefits from using Aerocapture instead of propulsive orbit insertion.
First, when a spacecraft use Aerocapture, it can deliver more payload mass to orbit, mean the destination. Simply, because the mass of hardware needed for the Aerocapture maneuver is less than the propulsion hardware and propellant needed to perform the insertion. This difference is available for increased science payload and spacecraft subsystems to support it.
Second, it decreases the trip time from launch at Earth to the destination. Why? Because we have a higher V∞ of approach from shortening a mission’s trip time, the ΔV for orbit insertion increases.Finally, we can also say that, given a fixed science payload and trajectory, Aerocapture allow launching on a less costly launch vehicle. That cost price depends strongly upon the destination, especially the destination’s heliocentric distance. Studies by NASA’s Aerocapture Systems Analysis Team (ASAT)indicate that the increase in delivered payload can range from about 15% at Mars, to more than 200% at Titan and Uranus, to more than 800% at Neptune.
NASA’s Orion spacecraft launched successfully atop a United Launch Alliance Delta IV Heavy rocket Dec. 5 at 7:05 a.m. EST from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. Orion’s Exploration Flight Test-1 (EFT-1), is the first flight test for NASA’s new deep space capsule and is a critical step on NASA's journey to Mars. The 4.5 hour flight is scheduled to conclude with the splashdown of Orion in the Pacific Ocean.
Orion entered two orbits of Earth. And 3 hours and 6 minutes after launch it swung out to its peak height of 3,604 miles up, higher than any spacecraft designed to carry humans has gone since Apollo. A few minutes later, Orion jettisoned the last piece of the Delta rocket, the second stage, and its service module, flying free for the first time Orion started it's return back to earth. Orion reached a re-entry speed of about 20,000 mph then deployed three sets of parachutes to splash down in the Ocean 4 hours and 24 minutes after it's flawless liftoff. Congratulations to NASA,ULA and all that made this close to perfect test flight A wonderful success. This video was edited for time. For other related videos please subscribe or go to my channel. Thank you for watching.
U.S. Navy divers from USS Anchorage (LPD 23) recover the NASA Orion space capsule after it splashed down in the Pacific Ocean on December 5, 2014. The recovery operation marked the end of Exploration Flight Test 1 (EFT-1), the first orbital test flight of the Orion spacecraft.